1. Field of the Invention
The present invention relates to a lumbar support apparatus and, more particularly, to a lumbar support for vehicle seats.
2. Description of the Related Art
In a conventional lumbar support apparatus disclosed, for example, in Japanese Patent Publication No. 55 (1980)-14647 and shown in FIGS. 5 and 6 herein, a seat frame 21 is provided with support members 22, 23 made of an elastic material such as wire formed in a sinusoidal pattern to constitute an S-spring. Members 22, 23 support the lumbar portion of the back at the lower portion of the seat frame 21. The seat frame 21 and support members 22, 23 are covered by, for example, vinyl, leather or cloth.
When lever 24 is moved upwardly, lock pins 25 connected to lever 24 are disengaged and slide rails 26, to which the support member 22 is fixed, are movable to permit forward and rearward movement of the support member 22 to thereby adjust the seat back on the seat frame 21. However, when support member 22 is permitted to extend forward of the seat when the lumbar support is operated, the difference between the fronts of support members 22 and 23 may become so large that it creates discomfort to the back of the user approximately along the portion A of the support member 22.